When a district or school staff member receives an information request, the first question he or she needs to consider is what type of information is being requested. Generally, an information request about one or more individuals can be categorized as nonpersonally identifiable information or personally identifiable information.
Nonpersonally identifiable data do not reveal specific information about a particular individual. They usually describe a group of persons (e.g., the aggregate number of students participating in extracurricular activities) without identifying any one student. Or they consist of individual records stripped of any information that would make it possible to identify the person described.
Release of nonpersonally identifiable data is generally allowed. A district or school may determine how this type of information is released. It is advisable to designate appropriate officials within the agency to review the compiled data, making sure that no single individual can be identified by a combination of several pieces of nonpersonally identifiable information.
For example, the release of school-level enrollment counts does not constitute releasing of personally identifiable information. However, enrollments by race or other demographic categories against various performance measures are clearly subject to cell suppression, if the cell size is low. Small cell sizes allow an audience to discern personally identifiable information about an individual. It is good practice for state and local education agencies to develop cell suppression guidelines regarding the release of aggregate data, in order to avoid the inadvertent violation of the confidentiality rights of students.
In planning and producing analyses and tabulations, the general rule is that there should be no cell (or category) published in which there are fewer than three respondents, or in which personal information could be obtained by subtraction or other simple mathematical manipulations. However, this should be adjusted based on the factors unique to the district or school, such as the size of the school or community population. It is important not to allow information to be disclosed through subsequent cross-tabulation of the same data with other variables.
An associated issue is whether or not a statistic is based upon a sufficient number of observations to be reliable as a measure of what it is intended to measure. Even if individual identities are adequately masked, the value of a cell may need to be suppressed because the value fails to meet reasonable criteria for reliability. In a paper entitled ďWhy a Small n Is Surrounded by Confidentiality: Ensuring Confidentiality and Reliability in Microdatabases and Summary Tables,Ē Ligon, Clements, and Paredes (2000) suggest useful solutions for protecting an individualís confidential information and describe the conditions under which statistics should be suppressed because the contents are based upon too few individuals to be reliable. The paper also includes a checklist to ensure the confidentiality of individuals when releasing statistics.
Personally identifiable data may or may not identify a person directly, but may contain information that would make a studentís identity easily recognized. This information is more sensitive than grouped information or summarized data and therefore requires more attention and care before release. Personally identifiable information, including the identifying data listed below, must be maintained in education records that are protected with appropriate security. It is important that state or local education agencies establish policies that define personally identifiable information and list specific examples. This will avoid confusion when actual information requests are handled.
Personally identifiable data often are unique to an individual, alone or in combination with other data, such as:
Some types of identifying data may be defined as part of the directory information in a districtís education records policy. Staff should check with the policy for the proper release of this type of information. Section 6B discusses directory information and its proper release.